Method and apparatus for network function service discovery

ABSTRACT

Embodiments of the present disclosure provide methods, apparatus and computer program products for network function service discovery. A method implemented at a second network node in a wireless core network with service based architecture comprises: receiving a registration request for network function instance from a network function, the registration request comprising information identifying a subscriber group to which the network function instance is applicable; and storing the information in association with the network function instance. With embodiments of the disclosure, size of NF profile can be saved.

PRIORITY

This nonprovisional application is a U.S. National Stage Filing under 35U.S.C. § 371 of International Patent Application Serial No.PCT/CN2018/104780 filed Sep. 10, 2018 and entitled “METHOD AND APPARATUSFOR NETWORK FUNCTION SERVICE DISCOVERY” which claims priority toInternational Patent Application No. PCT/CN2017/106059 filed Oct. 13,2017 both of which are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

The non-limiting and exemplary embodiments of the present disclosuregenerally relate to the technical field of wireless communications, andspecifically to methods, apparatuses and computer programs for networkfunction service discovery.

BACKGROUND

This section introduces aspects that may facilitate a betterunderstanding of the disclosure. Accordingly, the statements of thissection are to be read in this light and are not to be understood asadmissions about what is in the prior art or what is not in the priorart.

Currently core network architecture for next generation (5G) network hasbeen proposed. The 5G core network employs service based architecture(SBA). FIG. 1 shows a high level architecture of 5G core network SBA. In5G core network SBA, conventional network elements in LTE network arereplaced with network functions (NF). Each NF may provide many NFservices. As shown in FIG. 1, 5G core network SBA may comprise AMF(Access and mobility Function), SMF (Session Management Function), AUSF(Authentication Service Function), UDM (Unified Data Management), PCF(Policy Control Function), AF (Application Function), NEF (NetworkExposure Function), and NRF (NF Repository Function).

NRF may support NF service registration and NF service discovery. Forthe NRF to properly maintain information of available NF instances andtheir supported services, each NF instance informs the NRF of a list ofNF services that it supports and other NF instance information duringthe NF service registration. Each NF instance may have a NF profile. TheNF profile may include NF instance identifier (ID), NF type, PLMN ID,network slice related identifier(s), FQDN (Fully Qualified Domain Name)or IP address of NF, NF capacity information, names of supportedservices, endpoint information of instance(s) of each supported service,etc.

The NF service discovery may be implemented by supporting NF discovery(which may be also referred to as “NF selection”) using the NRF. The NFselection consists in selecting one NF instance among the NF instance(s)discovered during the NF service discovery. The NF selection may beimplemented by a requester NF. For example, UDM selection may beimplemented by the AMF.

SUMMARY

Various embodiments of the present disclosure mainly aim at providingmethods, apparatuses and computer programs for network function servicediscovery. Other features and advantages of embodiments of the presentdisclosure will also be understood from the following description ofspecific embodiments when read in conjunction with the accompanyingdrawings, which illustrate, by way of example, the principles ofembodiments of the present disclosure.

In a first aspect of the disclosure, there is provided a methodimplemented at a first network node in a wireless core network withservice based architecture. The method may comprise: determining, inresponse to trigger of network function selection for a terminal deviceof the wireless core network, at least one subscriber group that theterminal device is matched with; retrieving at least one networkfunction instance for the at least one subscriber group; and storing theat least one network function instance in association with the at leastone subscriber group.

In some embodiment, the method may further comprise obtaining subscribergroup information of a plurality of subscriber groups.

In some embodiment, the subscriber group information may comprise asubscriber group identifier or a policy of deriving a subscriber groupidentifier.

In some embodiment, the subscriber group identifier may be representedby one of at least one International Mobile Subscriber Identity (IMSI)range, a portion of Network Access Identifier (NAI), and a part or wholeof network slice selection information.

In some embodiments, the subscriber group identifier may be anidentifier mapped to at least one International Mobile SubscriberIdentity (IMSI) range or a portion of Network Access Identifier (NAI) ora part or whole of network slice selection information.

In some embodiments, the subscriber group identifier may be specific toa network function.

In some embodiments, determining at least one subscriber group that theterminal device is matched with may comprise: obtaining a subscriberidentifier of the terminal device and/or network slice selectioninformation provided by the terminal device; comparing the subscriberidentifier of the terminal device and/or the network slice selectioninformation with subscriber group identifiers of a plurality ofsubscriber groups; and determining, in response to the subscriber groupidentifier being a part of the subscriber identifier and/or a part ofthe network slice selection information, the terminal device is matchedwith the subscriber group having the subscriber group identifier.

In some embodiments, determining at least one subscriber group that theterminal device is matched with may comprise: obtaining a subscriberidentifier of the terminal device and/or network slice selectioninformation provided by the terminal device; and deriving at least onesubscriber group identifier from the subscriber identifier and/or thenetwork slice selection information.

In some embodiments, retrieving at least one network function instancecorresponding to the at least one subscriber group may comprise: sendinga first request for discovering network function instance, the firstrequest comprising a subscriber group identifier of the at least onesubscriber group; and receiving a first response comprising at least onenetwork function instance for the subscriber group.

In some embodiments, the method may further comprise checking whetherany network function instance has been cached locally for the subscribergroup that the terminal device is matched with. In an embodiment, theretrieving is performed in response to no network function instancebeing cached locally for the subscriber group.

In some embodiments, obtaining subscriber group information of aplurality of subscriber groups may comprise: sending a second requestfor querying subscriber group information of a plurality of subscribergroups; and receiving a second response comprising the subscriber groupinformation.

In some embodiments, obtaining subscriber group information of aplurality of subscriber groups may comprise receiving the subscribergroup information from another first network node.

In some embodiments, the subscriber identifier of the terminal devicemay be an IMSI or a NAI.

In some embodiments, the first network node may be a network functionservice consumer.

In a second aspect of the disclosure, there is provided a methodimplemented at a second network node in a wireless core network withservice based architecture. The method may comprise: receiving aregistration request for network function instance from a networkfunction, the registration request comprising information identifying asubscriber group to which the network function instance is applicable;and storing the information in association with the network functioninstance.

In some embodiment, the information is represented by one of asubscriber group identifier, an International Mobile Subscriber Identity(IMSI) range, two or more IMSI ranges, and a part or whole of networkslice selection information. The subscriber group identifier can be aportion of Network Access Identifier (NAI). The network slice selectioninformation may include Network Slice Selection Assistance Information(NSSAI).

In some embodiments, the information is mapped to one of a subscribergroup identifier, at least one International Mobile Subscriber Identity(IMSI) range, or a part or whole of network slice selection information.The subscriber group identifier can be a portion of NAI. The networkslice selection information may include NSSAI.

In some embodiments, the method may further comprise: receiving a firstrequest for discovering network function instance, the first requestcomprising information for a subscriber group; determining at least onenetwork function instance for the subscriber group, according to theinformation for the subscriber group and the second network node'sstorage; and sending a first response comprising the at least onenetwork function instance for the subscriber group.

In some embodiments, the method may further comprise: receiving a secondrequest for querying subscriber group information of a plurality ofsubscriber group; and sending a second response comprising thesubscriber group information of the plurality of subscriber group.

In some embodiments, the information for a subscriber group may comprisea subscriber group identifier or a policy of deriving a subscriber groupidentifier.

In some embodiments, the subscriber group identifier may be specific toa network function.

In some embodiments, the method may further comprise receivingregistration of a network function instance and information identifyinga subscriber group to which the network function instance is applicablevia a third party registration entity.

In some embodiments, the second network node may be a network functionrepository.

In a third aspect of the disclosure, there is provided a methodimplemented at a third network node in a wireless core network withservice based architecture. The method may comprise: registering, bysending a registration request for network function instance to a secondnetwork node. The registration request comprises information identifyinga subscriber group to which the network function instance is applicable.The second network node is a network function repository.

In some embodiments, the third network node is a network function or athird party registration entity.

In a fourth aspect of the disclosure, there is provided an apparatus ina first network node in a wireless core network with service basedarchitecture. The apparatus may comprise a processor and a memorycoupled to the processor. The memory may contain instructions executableby the processor, whereby the apparatus is operative to: determine, inresponse to trigger of network function selection for a terminal deviceof the wireless core network, at least one subscriber group that aterminal device of the wireless core network is matched with, retrieveat least one network function instance for the at least one subscribergroup, and store the at least one network function instance inassociation with the at least one subscriber group.

In some embodiments, the apparatus is further operative to obtainsubscriber group information of a plurality of subscriber groups.

In some embodiments, the apparatus is operative to obtain a subscriberidentifier of the terminal device and/or network slice selectioninformation provided by the terminal device, compare the subscriberidentifier of the terminal device and/or the network slice selectioninformation with subscriber group identifiers of a plurality ofsubscriber groups, and determine, in response to the subscriber groupidentifier being a part of the subscriber identifier and/or a part ofthe network slice selection information, the terminal device is matchedwith the subscriber group having the subscriber group identifier.

In some embodiments, the apparatus is operative to: obtain a subscriberidentifier of the terminal device and/or network slice selectioninformation provided by the terminal device, and derive at least onesubscriber group identifier from the subscriber identifier and/or thenetwork slice selection information.

In some embodiments, the apparatus is operative to: send a first requestfor discovering network function instance, the first request comprisinga subscriber group identifier of the at least one subscriber group, andreceive a first response comprising at least one network functioninstance for the subscriber group.

In some embodiments, the apparatus is further operative to check whetherany network function instance has been cached locally for the subscribergroup that the terminal device is matched with. In an embodiment, theapparatus is operative to retrieve the at least one network functioninstance in response to no network function instance being cachedlocally for the subscriber group.

In some embodiments, the apparatus is operative to: send a secondrequest for querying subscriber group information of a plurality ofsubscriber groups, and receive a second response comprising thesubscriber group information.

In a fifth aspect of the disclosure, there is provided an apparatus in asecond network node in a wireless core network with service basedarchitecture. The apparatus may comprise a processor and a memorycoupled to the processor. The memory may contain instructions executableby the processor, whereby the apparatus is operative to: receive aregistration request for network function instance from a networkfunction, the registration request including information identifying asubscriber group to which the network function instance is applicable,and store the information identifying the subscriber group inassociation with the network function instance.

In some embodiments, the apparatus is further operative to: receive afirst request for discovering network function instance, the firstrequest comprising information for a subscriber group, determine atleast one network function instance for the subscriber group, accordingto the information for the subscriber group and the second networknode's storage, and send a first response comprising the at least onenetwork function instance for the subscriber group.

In some embodiments, the apparatus is further operative to: receive asecond request for querying subscriber group information of a pluralityof subscriber group, and send a second response comprising thesubscriber group information of the plurality of subscriber group.

In some embodiments, the apparatus is further operative to receiveregistration of a network function instance and information identifyinga subscriber group to which the network function instance is applicablevia a third party registration entity.

In a sixth aspect of the disclosure, there is provided an apparatus in athird network node in a wireless core network with service basedarchitecture. The apparatus may comprise a processor and a memorycoupled to the processor. The memory may contain instructions executableby the processor, whereby the apparatus is operative to send aregistration request for network function instance to a second networknode, the registration request comprising information identifying asubscriber group to which the network function instance is applicable,wherein the second network node is a network function repository.

In a seventh aspect of the present disclosure, there is provided anapparatus in a first network node in a wireless core network withservice based architecture. The apparatus may comprise: a firstdetermining unit configured to determine, in response to trigger ofnetwork function selection by a terminal device of the wireless corenetwork, at least one subscriber group that a terminal device of thewireless core network is matched with; a retrieving unit configured toretrieve at least one network function instance for the at least onesubscriber group; and a storing unit configured to store the at leastone network function instance in association with the at least onesubscriber group.

In an eighth aspect of the present disclosure, there is provided anapparatus in a second network node in a wireless core network withservice based architecture. The apparatus may comprise: a thirdreceiving unit configured to receive a registration request for networkfunction instance from a network function, the registration requestcomprising information identifying a subscriber group to which thenetwork function instance is applicable; and a storing unit configuredto store the information in association with the network functioninstance.

In a ninth aspect of the present disclosure, there is provided anapparatus in a third network node in a wireless core network withservice based architecture. The apparatus may comprise a registeringunit configured to register by sending a registration request fornetwork function instance to a second network node, the registrationrequest comprising information identifying a subscriber group to whichthe network function instance is applicable, wherein the second networknode is a network function repository.

In a tenth aspect of the disclosure, there is provided an apparatus in afirst network node. The apparatus may comprise process means adapted toperform any method in accordance with the first aspect of thedisclosure.

In an eleventh aspect of the disclosure, there is provided an apparatusin a second network node. The apparatus may comprise process meansadapted to perform any method in accordance with the second aspect ofthe disclosure.

In a twelfth aspect of the disclosure, there is provided an apparatus ina third network node. The apparatus may comprise process means adaptedto perform any method in accordance with the third aspect of thedisclosure.

In a thirteenth aspect of the disclosure, there is provided a computerprogram, comprising instructions which, when executed on at least oneprocessor, cause the at least one processor to carry out the methodaccording to the first aspect of the disclosure.

In a fourteenth aspect of the disclosure, there is provided a computerprogram, comprising instructions which, when executed on at least oneprocessor, cause the at least one processor to carry out the methodaccording to the second aspect of the disclosure.

In a fifteenth aspect of the disclosure, there is provided a computerprogram, comprising instructions which, when executed on at least oneprocessor, cause the at least one processor to carry out the methodaccording to the second aspect of the disclosure.

According to the various aspects and embodiments as mentioned above, NFservice discovery can be based on the subscriber group identifier, andthe discovery result can be reusable and cacheable.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and benefits of variousembodiments of the present disclosure will become more fully apparent,by way of example, from the following detailed description withreference to the accompanying drawings, in which like reference numeralsor letters are used to designate like or equivalent elements. Thedrawings are illustrated for facilitating better understanding of theembodiments of the disclosure and not necessarily drawn to scale, inwhich:

FIG. 1 illustrates a schematic 5G core network with SBA;

FIG. 2 illustrates a flowchart of a method implemented at a firstnetwork node in a wireless core network with service based architectureaccording to an embodiment of the present disclosure;

FIG. 3 illustrates a flowchart of a method implemented at a firstnetwork node in a wireless core network with service based architectureaccording to another embodiment of the present disclosure;

FIG. 4 illustrate a flowchart of a method implemented at a secondnetwork node in a wireless core network with service based architectureaccording to an embodiment of the present disclosure;

FIG. 5 illustrates a flowchart of a method implemented at a secondnetwork node in a wireless core network with service based architectureaccording to another embodiment of the present disclosure;

FIG. 6 illustrate a flowchart of method implemented at a third networknode in a wireless core network with service based architectureaccording to an embodiment of the present disclosure;

FIG. 7 illustrates an exemplary flow of network function servicediscovery according to embodiments of the present disclosure;

FIGS. 8a-8c illustrate simplified block diagrams of an apparatus in afirst network node, a second network node and a third network node,respectively, according to an embodiment of the present disclosure;

FIG. 9 illustrates a simplified block diagram of an apparatus in a firstnetwork node according to an embodiment of the present disclosure;

FIG. 10 illustrates a simplified block diagram of an apparatus in asecond network node according to an embodiment of the presentdisclosure; and

FIG. 11 illustrates a simplified block diagram of an apparatus in athird network node according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, the principle and spirit of the present disclosure will bedescribed with reference to illustrative embodiments. It should beunderstood, all these embodiments are given merely for one skilled inthe art to better understand and further practice the presentdisclosure, but not for limiting the scope of the present disclosure.For example, features illustrated or described as part of one embodimentmay be used with another embodiment to yield still a further embodiment.In the interest of clarity, not all features of an actual implementationare described in this specification.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc. indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but it isnot necessary that every embodiment includes the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

It shall be understood that, although the terms “first” and “second”etc. may be used herein to describe various elements, these elementsshould not be limited by these terms. These terms are only used todistinguish one element from another. For example, a first element couldbe termed a second element, and similarly, a second element could betermed a first element, without departing from the scope of exampleembodiments. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed terms.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be liming of exampleembodiments. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises”, “comprising”, “has”, “having”, “includes” and/or“including”, when used herein, specify the presence of stated features,elements, and/or components etc., but do not preclude the presence oraddition of one or more other features, elements, components and/orcombinations thereof.

In the following description and claims, unless defined otherwise, alltechnical and scientific terms used herein have the same meaning ascommonly understood by one of ordinary skills in the art to which thisdisclosure belongs. For example, the term “terminal device” used hereinmay refer to any terminal device or user equipment (UE) having wirelesscommunication capabilities, including but not limited to, mobile phones,cellular phones, smart phones, or personal digital assistants (PDAs),portable computers, image capture devices such as digital cameras,gaming devices, music storage and playback appliances, wearable devices,vehicle-mounted wireless device and the like. In the followingdescription, the terms “terminal device”, “user equipment” and “UE” maybe used interchangeably. Similarly, the term “network node” mayrepresent any NF in 5G core network.

For illustrative purposes, several embodiments of the present disclosurewill be described in the context of a 5G core network. Those skilled inthe art will appreciate, however, that the concept and principle of theseveral embodiments of the present disclosure may be more generallyapplicable to other wireless core networks with SBA.

The non-limiting and exemplary embodiments of the present disclosurerelate to NF service discovery.

In 5G core network as shown in FIG. 1, a NF may provide many NF servicesand a NF may request a certain NF service. In this case, the requestingNF may be referred to as “NF service consumer”, and the NF providing theNF service may be referred to as “NF service producer”. As describedabove, the NF services provided by the NF service producers may beregistered in the NRF.

3GPP requires that multiple UDM instances serving dedicated subscribergroups may be employed within one PLMN. Hence it shall be possible todiscover and select the UDM instance based on a subscriber identifier ofa terminal device. In 5G network, each terminal device shall beallocated with a globally unique 5G Subscriber Permanent Identifier(SUPI). The SUPI may have two types: International Mobile SubscriberIdentity (IMSI) as defined in TS 23.003 and Network Access Identifier(NAI) using the NAI RFC 4282 based user identification as defined inTS23.003.

Currently the NF service consumer performs the NF selection based on thesubscriber identifier of the terminal device in the NF service discoveryprocedure. However using the subscriber identifier of the terminaldevice in the NF service discovery would make the discovery resultunique per individual terminal device. Also the discovery result is notreusable when the NF service consumer performs the NF selection forother terminal device. Thus the overall network signaling load would beincreased.

In addition, when the NF service consumer performs the NF servicediscovery, the NRF will always keep a complete list of NF services forevery single subscriber identifier. This would increase the load of theNRF.

Considering the case where the UDM instances are deployed to thededicated subscriber groups, when the UDM performs UDM serviceregistration with the NRF, the UDM will indicate to the NRF whichsubscriber group the UDM instance will serve. When the AMF uses the SUPIof the terminal device to perform the NF service discovery for the UDMservice, the NRF has to compute and find out which subscriber group theSUPI belongs to. This would increase the complexity in the NRFimplementation.

On the other hand, the subscriber group may be configured locally in theNF service consumer. Hence only static NF instance information of the NFservice producer can be supported. The NF service consumer cannotconsider the dynamic NF instance information during the NF servicediscovery.

Therefore it is desirable to provide a new mechanism for NF servicediscovery to overcome the above mentioned problems.

In the present disclosure, methods, apparatuses and computer programproducts are provided to support NF service discovery in the wirelesscore network with SBA. Though embodiments of the present disclosure canbe implemented in the exemplary 5G core network shown in FIG. 1, itwould be appreciated that embodiments of the disclosure are not limitedto such a core network.

Reference is now made to FIG. 2, which shows a flowchart of a method 200according to an embodiment of the present disclosure. The method 200 maybe implemented at a first network node (e.g., a NF service consumer likethe AMF shown in FIG. 1).

As shown in FIG. 2, the method 200 may comprise: determining at leastone subscriber group that the terminal device is matched with at block210; retrieving at least one network function instance for the at leastone subscriber group at block 220; and storing the at least one networkfunction instance in association with the at least one subscriber groupat block 230.

In an embodiment, at block 210, the NF service consumer may determine,in response to trigger of the NF selection for the terminal device (e.g.NG UE as shown in FIG. 1), which subscriber group(s) the terminal deviceis matched with. For example, when the terminal device attaches to awireless network, or the terminal device originates traffic, or theterminal device terminates traffic, etc. the NF selection may betriggered for this terminal device. When an SMS (Short Message Service)message is sent to unattached terminal device and cached in the network,NF selection procedure can be invoked. When an SMS message is deliveredto a terminal device once it is attached in the network, NF selectionprocedure can be invoked. At this time, the NF service consumerperforming the NF selection may determine which subscriber group(s) theterminal device is matched with. The NF service consumer may make thedetermination based on subscriber group information of a plurality ofsubscriber groups and information provided by the terminal device. Thesubscriber group information of the subscriber groups may be stored inthe NF service consumer.

In some embodiments, the NF service consumer may obtain the subscribergroup information of the subscriber groups in advance at block 202. Asdescribed above, the NF service producer may register its NF serviceswith the NRF. The NRF may maintain the NF profile for each NF instance.During the NF service registration, the NF service producer may informthe NRF which subscriber group(s) the NF instance can serve. The NRF maystore the subscriber group information of the subscriber group(s) in theNF profile of the NF instance. In an embodiment, the NF service consumermay obtain the subscriber group information from the NRF. The NF serviceconsumer may send a request for querying the subscriber groupinformation to the NRF. For example, the request may be a HTTP requestlike GET. Then the NF service consumer may receive a response comprisingthe subscriber group information from the NRF.

In some embodiments, the subscriber group information may comprise asubscriber group identifier of the subscriber group. The subscribergroup identifier may be formed in various ways.

In an embodiment, the subscriber group identifier may be represented byone or more IMSI range. As described above, the subscriber identifier ofthe terminal device may be IMSI. Hence it is possible to use one or moreIMSI ranges to represent a subscriber group.

Alternatively, in an embodiment, the subscriber group identifier may berepresented by a portion of NAI. As described above, the subscriberidentifier of the terminal device may be NAI. Generally, the NAI may bein the form of “Username@Domain”. Hence the portion of “Username” or“Domain” may be used as the subscriber group identifier. In this case,the subscriber group may comprise a number of terminal devices with thesame “Username” or “Domain”. Alternatively, a part of the portion of“Username” or “Domain” may be used as the subscriber group identifier.

Alternatively, in an embodiment, the subscriber group identifier may berepresented by a part or whole of network slice selection information,such as NSSAI (Network Slice Selection Assistance Information). Theterminal device may provide the NSSAI to select a certain network slice.Hence the NSSAI may be used to identify a number of terminal devices.

Alternatively, in an embodiment, the subscriber group identifier may bemapped to one or more IMSI ranges, or a portion of NAI, or a part orwhole of the NSSAI.

In some embodiments, the subscriber group information may be a policy ofderiving a subscriber group identifier. The policy may indicate how thesubscriber group identifier can be derived from the information of theterminal device, e.g. the subscriber identifier of the terminal deviceor the network slice selection information provided by the terminaldevice.

In some embodiments, the subscriber group identifier may be specific toa NF. In an embodiment, the subscriber group identifier may be specificto the NF service producer. That is, different NF service producers mayhave different forms of subscriber group identifier. For example, UDMmay have the subscriber group identifier in the form of IMSI range, andSMF may have the subscriber group identifier in the form of a part ofNSSAI. Alternatively or additionally, the subscriber group identifiermay be specific to the NF service consumer. For example, only specificsubscriber group identifier may be used by the NF service consumer.

In some embodiments, the NF service consumer may obtain the subscribergroup information by receiving the subscriber group information fromanother NF service consumer that has cached the subscriber groupinformation. For example, when the terminal device reattaches to newAMF, the new AMF may be received the subscriber group information fromthe old AMF.

Back to the block 210, the NF service consumer may determine thesubscriber group(s) that the terminal device is matched with. In someembodiments, the NF service consumer may obtain the subscriberidentifier of the terminal device and/or the network slice selectioninformation provided by the terminal device. Then the NF serviceconsumer may compare the subscriber identifier and/or the network sliceselection information with the subscriber group identifiers of thesubscriber groups. If any subscriber group identifier is a part of thesubscriber identifier and/or a part of the network slice selectioninformation provided by the terminal device, it is determined that theterminal device belongs to the subscriber group having the subscribergroup identifier. It should be noted that in this case, the NF serviceconsumer has obtained the subscriber group identifiers of the subscribergroups.

In some embodiments, the NF service consumer may obtain the subscriberidentifier of the terminal device and/or the network slice selectioninformation provided by the terminal device. Then the NF serviceconsumer may derive the subscriber group identifier from the subscriberidentifier and/or the network slice selection information. It should benoted that in this case, the NF service consumer has obtained the policyof deriving the subscriber group identifier.

Then at block 220, the NF service consumer may retrieve at least onenetwork function instance corresponding to the matched subscribergroup(s). In some embodiments, the NF service consumer may send arequest for discovering the NF instance to the NRF. The request maycomprise the subscriber group identifier(s) of the matched subscribergroup(s). The NRF may discover the NF instance(s) based on thesubscriber group identifier(s). Then the NRF may send a responseincluding the discovered NF instance(s) to the NF service consumer.

Then at block 230, the NF service consumer may store the received NFinstance(s) in association with the subscriber group identifier(s). Thusthe stored NF instances are reusable for the terminal devices belongingto the corresponding subscriber group. In some embodiments, the NFservice consumer may store the NF instance(s) for a certain period.After the period expires, the NF service consumer should retrieve the NFinstance again. In this way, the NF service consumer can update thestored NF instances. Then the NF service consumer may proceed withrequesting the NF service with the NF service producer.

FIG. 3 illustrates a flowchart of a method 300 implemented at the firstnetwork node according to another embodiment of the present disclosure.In the method 300, after determining the subscriber group(s) that theterminal device is matched with at block 210, at block 310, the NFservice consumer may check whether any NF instance has been cachedlocally for the matched subscriber group(s). If the NF instances for thematched subscriber group(s) have been cached locally, there is no needfor the NF service consumer to perform the operations at blocks 220,230. If no NF instance for the matched subscriber group(s) has beencached locally, the NF service consumer may perform the operations atblocks 220, 230.

Reference is now made to FIG. 4, which shows a flowchart of a method 400according to an embodiment of the present disclosure. The method 400 maybe implemented at a second network node (e.g., a NF repository like theNRF shown in FIG. 1).

As shown in FIG. 4, the method 400 may comprise: receiving aregistration request for network function instance from a networkfunction service producer at block 410, the registration requestincluding a subscriber group identifier of a subscriber group to whichthe network function instance is applicable; and storing the subscribergroup identifier in association with the network function instance atblock 420.

As described above, the NF instances are registered in the NRF, and theNRF maintains the NF profile for the NF instance. The NF registrationmay be triggered by the NF service producer or via a third partyregistration entity.

At block 410, the NF repository may receive a registration request for aNF instance from the NF service producer. The registration request maycomprise a subscriber group identifier of a subscriber group to whichthe NF instance is applicable. Then at block 420, the NF repository maystore the NF instance in association with the subscriber groupidentifier. In an embodiment, the NF repository may store the subscribergroup identifier in the NF profile for the NF instance.

Alternatively or additionally, in some embodiments, the NF repositorymay receive registration of a NF instance and a subscriber groupidentifier of a subscriber group to which the NF instance is applicablevia a third party registration entity. For example, the third partyregistration entity may be an OAM (Operation and Management) function.

In some embodiments, the subscriber group identifier may be representedby one of at least one IMSI range, a portion of NAI, and a part or wholeof network slice selection information. Alternatively, the subscribergroup identifier may be mapped to at least one IMSI range or a portionof NAI or a part or whole of network slice selection information.

With the embodiments described above, since information for thesubscriber group, other than each of an entire subscriber identifier inthe subscriber group, is registered associated with the networkinstance, size of NF profile can be saved. Further, signaling on theinterfaces between the NFR and the register requester can be reduced.

FIG. 5 illustrates a flow of a method 500 implemented at the secondnetwork node according to another embodiment of the present disclosure.As shown in FIG. 5, the NF repository may further provide the subscribergroup information of the subscriber group to the NF service consumer andperform NF service discovery with the NF service consumer.

At block 510, the NF repository may receive a request for querying thesubscriber group information from the NF service consumer. In someembodiments, the request may be a HTTP request, e.g. GET. Then the NFrepository, in response to the request, provide the subscriber groupinformation including the subscriber group identifiers and/or the policyof deriving the subscriber group identifier to the NF service consumer,at block 520.

In parallel, the NF repository may receive a request for discovering NFinstance from the NF service consumer, at block 530. The request mayinclude the subscriber group identifier of the subscriber group. Thenthe NF repository may discover one or more NF instances according to thesubscriber group identifier at block 540. As described above, the NFrepository may store the subscriber group identifier in the NF profilefor the NF instance. Then at block 550, the NF repository may send thediscovered NF instances as a response to the NF service consumer.

Reference is now made to FIG. 6, which shows a flowchart of a method 600according to an embodiment of the present disclosure. The method 600 maybe implemented at a third network node (e.g., a NF service producer likethe UDM, SMF, AUSF, PCF, etc. shown in FIG. 1).

As shown in FIG. 6, at block 610, the NF service producer may registerwith the NF repository a NF instance together with a subscriber groupidentifier of a subscriber group to which the NF instance is applicable.In this way, the NF service producer can inform the NF repository thesubscriber group its NF instance will serve.

With the embodiments of the present disclosure as described above, theNF service discovery can be performed based on the subscriber groupidentifier of the subscriber group. Compared with using the subscriberidentifier of the terminal device to perform the NF service discovery,using the subscriber group identifier can make the discovery resultreusable/cacheable for the NF service consumer, thereby reducing theoverall network signaling load. Moreover, it allows for dynamicinformation of the NF service producers to be discovered.

FIG. 7 illustrates an exemplary flow of the NF service discoveryaccording to the embodiments of the present disclosure. In this example,it takes AMF as an example of the NF service consumer, UDM as an exampleof the NF service producer, and NRF as an example of the NF repository.

As shown in FIG. 7, the AMF may obtain the subscriber group informationfrom the NRF. This procedure may be performed as described in connectionwith block 202 of FIG. 2 and blocks 510, 520 of FIG. 5. On the otherhand, the UDM may register its UDM instances together with thesubscriber group identifier(s) of the subscriber group(s) to which theUDM instances serve with the NRF. This procedure may be performed asdescribed in connection with block 410 of FIG. 4 and block 610 of FIG.6. Assume that the subscriber group identifier is represented by theIMSI range.

When UE-A (with the IMSI as 341000123456789) attaches to the corenetwork, the AMF may determine UE-A is matched with a subscriber groupwith the IMSI range 1 as 341000123. The AMF checks there is no localcache of UDM instance serving the subscriber group.

Then the AMF triggers the NF service discovery procedure using the IMSIrange 1 of 341000123. The AMF may send a request for discovering UDMinstance to the NRF. The request includes the IMSI range 1. Then the NRFdiscovers the UDM instances corresponding to the IMSI range 1 and sendthe discovered UDM instances to the AMF.

The AMF may store the received UDM instances in association with thesubscriber group with the IMSI range 1 in its local storage. Then AMFmay continue with subsequent operation, e.g. requesting UDM service.

When UE-B (with the IMSI as 34100123456788) attaches in the corenetwork, the AMF may determine that the UE-B is matched with thesubscriber group with the IMSI range 1. Then the AMF check that there isa local cache of the UDM instances serving the subscriber group. Thenthe AMF may skip the NF service discovery procedure and continue withthe subsequent operation, e.g. requesting UDM service.

FIG. 8a illustrates a simplified block diagram of an apparatus 810 thatmay be embodied in/as a first network node, e.g., the NF serviceconsumer like the AMF shown in FIG. 1. FIG. 8b illustrates an apparatus820 that may be embodied in/as a second network node, e.g., the NFrepository like NRF shown in FIG. 1. FIG. 8c shows an apparatus 830 thatmay be embodied in/as a third network node, e.g., the NF serviceproducer like the UDM, SMF, AUSF, etc. shown in FIG. 1.

The apparatus 810 may comprise at least one processor 811, such as adata processor (DP) and at least one memory (MEM) 812 coupled to theprocessor 811. The apparatus 810 may further comprise a transmitter TXand receiver RX 813 coupled to the processor 811. The MEM 812 stores aprogram (PROG) 814. The PROG 814 may include instructions that, whenexecuted on the associated processor 811, enable the apparatus 810 tooperate in accordance with the embodiments of the present disclosure,for example to perform the methods 200, 300. A combination of the atleast one processor 811 and the at least one MEM 812 may form processingmeans 815 adapted to implement various embodiments of the presentdisclosure.

The apparatus 820 comprises at least one processor 821, such as a DP,and at least one MEM 822 coupled to the processor 821. The apparatus 820may further comprise a transmitter TX and receiver RX 823 coupled to theprocessor 821. The MEM 822 stores a PROG 824. The PROG 824 may includeinstructions that, when executed on the associated processor 821, enablethe apparatus 820 to operate in accordance with the embodiments of thepresent disclosure, for example to perform the methods 400, 500. Acombination of the at least one processor 821 and the at least one MEM822 may form processing means 825 adapted to implement variousembodiments of the present disclosure.

The apparatus 830 comprises at least one processor 831, such as a DP,and at least one MEM 832 coupled to the processor 831. The apparatus 830may further comprise a transmitter TX and receiver RX 833 coupled to theprocessor 831. The MEM 832 stores a PROG 834. The PROG 834 may includeinstructions that, when executed on the associated processor 821, enablethe apparatus 830 to operate in accordance with the embodiments of thepresent disclosure, for example to perform the method 600. A combinationof the at least one processor 831 and the at least one MEM 832 may formprocessing means 835 adapted to implement various embodiments of thepresent disclosure.

Various embodiments of the present disclosure may be implemented bycomputer program executable by one or more of the processors 811, 821and 831, software, firmware, hardware or in a combination thereof.

The MEMs 812, 822 and 832 may be of any type suitable to the localtechnical environment and may be implemented using any suitable datastorage technology, such as semiconductor based memory devices, magneticmemory devices and systems, optical memory devices and systems, fixedmemory and removable memory, as non-limiting examples.

The processors 811, 821 and 831 may be of any type suitable to the localtechnical environment, and may include one or more of general purposecomputers, special purpose computers, microprocessors, digital signalprocessors DSPs and processors based on multicore processorarchitecture, as non-limiting examples.

Reference is now made to FIG. 9, which illustrates a schematic blockdiagram of an apparatus 900 in a first network node in a wireless corenetwork with SBA. The first network node may be, for example, the NFservice consumer like the AMF shown in FIG. 1. The apparatus 900 isoperable to carry out the exemplary methods 200, 300 described withreference to FIGS. 2-3 and possibly any other processes or methods.

As shown in FIG. 9, the apparatus 900 may comprise: a first determiningunit 901 configured to determine, in response to trigger of networkfunction selection by a terminal device of the wireless core network, atleast one subscriber group that a terminal device of the wireless corenetwork is matched with; a retrieving unit 902 configured to retrieve atleast one network function instance for the at least one subscribergroup; and a storing unit 903 configured to store the at least onenetwork function instance in association with the at least onesubscriber group.

In some embodiment, the apparatus 900 may further comprise a firstobtaining unit 904 configured to obtain subscriber group information ofa plurality of subscriber groups. In an embodiment, the subscriber groupinformation may comprise a subscriber group identifier and/or a policyof deriving a subscriber group identifier.

In some embodiments, the first determining unit 901 may comprise asecond obtaining unit 9011 configured to obtain a subscriber identifierof the terminal device and/or network slice selection informationprovided by the terminal device; a comparing unit 9012 configured tocomparing the subscriber identifier of the terminal device and/or thenetwork slice selection information with subscriber group identifiers ofa plurality of subscriber groups; and a second determining unit 9013configured to determine, in response to the subscriber group identifierbeing a part of the subscriber identifier and/or a part of the networkslice selection information, the terminal device is matched with thesubscriber group having the subscriber group identifier.

In some embodiments, the first determining unit 901 may comprise asecond obtaining unit configured to obtain a subscriber identifier ofthe terminal device and/or network slice selection information providedby the terminal device; and a deriving unit configured to derive atleast one subscriber group identifier from the subscriber identifierand/or the network slice selection information.

In some embodiments, the retrieving unit 902 may comprise a firstsending unit 9021 configured to send a first request for discoveringnetwork function instance, the first request comprising a subscribergroup identifier of the at least one subscriber group; and a firstreceiving unit 9022 configured to receive a first response comprising atleast one network function instance for the subscriber group.

In some embodiments, the apparatus 900 may further comprise a checkingunit 905 configured to check whether any network function instance hasbeen cached locally for the subscriber group that the terminal device ismatched with. In an embodiment, the retrieving unit 902 may beconfigured to retrieve the NF instance in response to no networkfunction instance being cached locally for the subscriber group.

In some embodiments, the first obtaining unit 904 may comprise a secondsending unit configured to send a second request for querying subscribergroup information of a plurality of subscriber groups; and a secondreceiving unit configured to receiving a second response comprising thesubscriber group information. In an embodiment, the first obtaining unit904 may be configured to receive the subscriber group information fromanother first network node.

In some embodiments, the units of the apparatus 900 may be configured toimplement the operations of corresponding blocks of the methods 200,300, and therefore relevant descriptions provided with reference tomethods 200, 300 also apply here and thus details will not be repeated.

Reference is now made to FIG. 10, which illustrates a schematic blockdiagram of an apparatus 1000 in a second network node in a wireless corenetwork with SBA. The second network node may be, for example, the NRFshown in FIG. 1. The apparatus 1000 is operable to carry out theexemplary methods 400, 500 described with reference to FIGS. 4-5 andpossibly any other processes or methods.

As illustrated in FIG. 10, the apparatus 1000 may comprises a thirdreceiving unit 1001 configured to receive a registration request fornetwork function instance from a network function service producer, theregistration request including a subscriber group identifier of asubscriber group to which the network function instance is applicable;and a storing unit 1002 configured to store the subscriber groupidentifier in association with the network function instance.

In some embodiments, the apparatus 1000 may further comprise a fourthreceiving unit 1003 configured to receive a first request fordiscovering network function instance, the first request comprising asubscriber group identifier of a subscriber group; a determining unit1004 configured to determine at least one network function instance forthe subscriber group, according to the subscriber group identifier; anda third sending unit 1005 configured to send a first response comprisingthe at least one network function instance for the subscriber group.

In some embodiments, the apparatus 1000 may further comprise a fifthreceiving unit 1006 configured to receive a second request for queryingsubscriber group information of a plurality of subscriber group; and afourth sending unit 1007 configured to send a second response comprisingthe subscriber group information of the plurality of subscriber group.

In some embodiments, the apparatus 1000 may further comprise a sixthreceiving unit 1008 configured to receive registration of a networkfunction instance and a subscriber group identifier of a subscribergroup to which the network function instance is applicable via a thirdparty registration entity.

In some embodiments, the units of the apparatus 1000 may be configuredto implement the operations of corresponding blocks of the methods 400,500, and therefore relevant descriptions provided with reference tomethods 400, 500 also apply here and thus details will not be repeated.

Reference is now made to FIG. 11, which illustrates a schematic blockdiagram of an apparatus 1100 in a third network node in a wireless corenetwork with SBA. The third network node may be, for example, the NFservice producer, like the UDM, AUSF, PCF, etc. shown in FIG. 1. Theapparatus 1100 is operable to carry out the method 600 described withreference to FIG. 6 and possibly any other processes or methods.

As shown in FIG. 11, the apparatus 1100 may comprise a registering unit1101 configured to register, with a network function repository, anetwork function instance together with a subscriber group identifier ofa subscriber group to which the network function instance is applicable.

It would be appreciated that, some units or modules in the apparatus900, 1000 or 1100 can be combined in some implementations. For example,in one embodiment, it is possible to use a single transceiving unit tosend and receive all the information transmitted by the units 1001,1003, 1005-1008 described with reference to FIG. 10.

Although some embodiments are described in the context of an exemplarynetwork shown in FIG. 1, it should not be construed as limiting thespirit and scope of the present disclosure. The principle and concept ofthe present disclosure may be more generally applicable to other networkarchitectures.

In addition, the present disclosure may also provide a carriercontaining the computer program as mentioned above, wherein the carrieris one of an electronic signal, optical signal, radio signal, orcomputer readable storage medium. The computer readable storage mediumcan be, for example, an optical compact disk or an electronic memorydevice like a RAM (random access memory), a ROM (read only memory),Flash memory, magnetic tape, CD-ROM, DVD, Blue-ray disc and the like.

The techniques described herein may be implemented by various means sothat an apparatus implementing one or more functions of a correspondingapparatus described with an embodiment comprises not only prior artmeans, but also means for implementing the one or more functions of thecorresponding apparatus described with the embodiment and it maycomprise separate means for each separate function, or means that may beconfigured to perform two or more functions. For example, thesetechniques may be implemented in hardware (one or more apparatuses),firmware (one or more apparatuses), software (one or more modules), orcombinations thereof. For a firmware or software, implementation may bemade through modules (e.g., procedures, functions, and so on) thatperform the functions described herein.

Exemplary embodiments herein have been described above with reference toblock diagrams and flowchart illustrations of methods and apparatuses.It will be understood that each block of the block diagrams andflowchart illustrations, and combinations of blocks in the blockdiagrams and flowchart illustrations, respectively, can be implementedby various means including computer program instructions. These computerprogram instructions may be loaded onto a general purpose computer,special purpose computer, or other programmable data processingapparatus to produce a machine, such that the instructions which executeon the computer or other programmable data processing apparatus createmeans for implementing the functions specified in the flowchart block orblocks.

Further, while operations are depicted in a particular order, thisshould not be understood as requiring that such operations be performedin the particular order shown or in sequential order, or that allillustrated operations be performed, to achieve desirable results. Incertain circumstances, multitasking and parallel processing may beadvantageous. Likewise, while several specific implementation detailsare contained in the above discussions, these should not be construed aslimitations on the scope of the subject matter described herein, butrather as descriptions of features that may be specific to particularembodiments. Certain features that are described in the context ofseparate embodiments may also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment may also be implemented in multipleembodiments separately or in any suitable sub-combination.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyimplementation or of what may be claimed, but rather as descriptions offeatures that may be specific to particular embodiments of particularimplementations. Certain features that are described in thisspecification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable sub-combination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a sub-combination or variation of a sub-combination.

It will be obvious to a person skilled in the art that, as thetechnology advances, the inventive concept can be implemented in variousways. The above described embodiments are given for describing ratherthan limiting the disclosure, and it is to be understood thatmodifications and variations may be resorted to without departing fromthe spirit and scope of the disclosure as those skilled in the artreadily understand. Such modifications and variations are considered tobe within the scope of the disclosure and the appended claims. Theprotection scope of the disclosure is defined by the accompanyingclaims.

What is claimed is:
 1. A method implemented at a second network node in a wireless core network with service based architecture, comprising: receiving a registration request for network function instance from a network function, the registration request comprising information identifying a subscriber group to which the network function instance is applicable; and storing the information in association with the network function instance.
 2. The method according to claim 1, wherein the information is represented by at least one of: a subscriber group identifier, at least one International Mobile Subscriber Identity (IMSI) range, and a part or whole of network slice selection information.
 3. The method according to claim 2, wherein the network slice selection information comprises Network Slice Selection Assistance Information (NSSAI); or wherein the subscriber group identifier comprises at least one of: a portion of Network Access Identifier (NAT).
 4. The method according to claim 1, further comprising: receiving a first request for discovering network function instance, the first request comprising information for a subscriber group; determining at least one network function instance for the subscriber group, according to the information for the subscriber group and the second network node's storage; and sending a first response comprising the at least one network function instance for the subscriber group.
 5. A method implemented at a third network node in a wireless core network with service based architecture, comprising: sending a registration request for network function instance to a second network node, the registration request comprising information identifying a subscriber group to which the network function instance is applicable; wherein the second network node is a network function repository.
 6. The method according to claim 5, wherein the third network node is a network function or a third party registration entity.
 7. The method according to claim 5, wherein the information is represented by at least one of: a subscriber group identifier, at least one International Mobile Subscriber Identity (IMSI) range, and a part or whole of network slice selection information; or wherein the information is mapped to at least one of: a subscriber group identifier, at least one IMSI range, and a part or whole of network slice selection information.
 8. The method according to claim 7, wherein the network slice selection information comprises Network Slice Selection Assistance Information (NSSAI); or wherein the subscriber group identifier comprises at least one of: a portion of Network Access Identifier (NAI).
 9. An apparatus in a second network node in a wireless core network with service based architecture, comprising: a processor; and a memory coupled to the processor, said memory containing instructions executable by said processor, whereby said apparatus is operative to: receive a registration request for network function instance from a network function, the registration request comprising information identifying a subscriber group to which the network function instance is applicable; and store the information in association with the network function instance.
 10. The apparatus according to claim 9, wherein the information is represented by at least one of: a subscriber group identifier, at least one International Mobile Subscriber Identity (IMSI) range, and a part or whole of network slice selection information; or wherein the information is mapped to at least one of: a subscriber group identifier, at least one International Mobile Subscriber Identity (IMSI) range, and a part or whole of network slice selection information.
 11. The apparatus according to claim 9, wherein the network slice selection information comprises NSSAI; or wherein the subscriber group identifier comprises at least one of: a portion of NAI.
 12. The apparatus according to claim 9, wherein the network function is a Unified Data Management (UDM), Access and mobility Function (AMF), Network Exposure Function (NEF), Session Management Function (SMF), Authentication Service Function (AUSF) or Policy Control Function (PCF).
 13. The apparatus according to claim 9, further adapted to: receive a first request for discovering network function instance, the first request comprising information for a subscriber group; determine at least one network function instance for the subscriber group, according to the information for the subscriber group and the second network node's storage; and send a first response comprising the at least one network function instance for the subscriber group.
 14. An apparatus in a third network node in a wireless core network with service based architecture, comprising: a processor; and a memory coupled to the processor, said memory containing instructions executable by said processor, whereby said apparatus is operative to: send a registration request for network function instance to a second network node, the registration request comprising information identifying a subscriber group to which the network function instance is applicable; wherein the second network node is a network function repository.
 15. The apparatus according to claim 14, wherein the third network node is a network function or a third party registration entity.
 16. The apparatus according to claim 15, wherein when the third network node is a network function, it is one of: a Unified Data Management (UDM), Access and mobility Function (AMF), Network Exposure Function (NEF), Session Management Function (SMF), Authentication Service Function (AUSF) and Policy Control Function (PCF).
 17. The apparatus according to claim 14, wherein the information is represented by at least one of: a subscriber group identifier, at least one International Mobile Subscriber Identity (IMSI) range, and a part or whole of network slice selection information; or wherein the information is mapped to at least one of: a subscriber group identifier, at least one IMSI range, and a part or whole of network slice selection information.
 18. The apparatus according to claim 17, wherein the network slice selection information comprises Network Slice Selection Assistance Information (NSSAI); or wherein the subscriber group identifier comprises at least one of: a portion of Network Access Identifier (NAI). 